Data taken from the literature on receptor-mediated stimulation of adenylate cyclase have been reviewed and analyzed to determine whether and to what extent these data are compatible with several previously proposed mechanistic molecular models and extensions thereof. The kinetics of appearance of fibrinopeptides following the addition of thrombin or other specific enzymes to fibrinogen are being measured via amino acid analysis of fibrinopeptide hydrolyzates. The kinetics of appearance of small soluble oligomers of fibrinogen/fibrin at early times in the fibrin gelation reaction are being measured via a novel application of high performance gel exclusion chromatography. The dependence of fibrin gelation time upon initial concentrations of fibrinogen and thrombin, upon the delay time preceding addition of a thrombin inhibitor, and upon the concentration of unrelated globular proteins present in the reaction mixture, is being measured using a novel viscometric technique. An automated method is being developed for measuring the concentration gradient of individual macromolecular species in a centrifuged solution containing several macromolecular solutes.